Apparatus for electroplating sheet metal



Se t. 21, 1937. M. SCHLOTTER 2,093;484

APPARATUS FOR ELECTROPLATING SHEET METAL Filed Aug. 15, 1955 2 Sheets-Sheet 2 INVENTO. I

BYM

: ATTORNEYS Patented Sept. 21, 19 37 PATENT OFFICE 2,093,484 armasrus roa amomormme sans-r man * Max Schliitter, nerun, Germany Application August is, 1935, Serial No. 36,457

Germany April 3, 1935 10 Claims.

My invention relates to apparatus for electroplating metal sheets in continuous succession.

An object of my invention is to increase the output or capacity of electroplating apparatus 5 and to simplify the operation of such apparatus. I In my invention successive metal sheets are automatically secured and held in position by electro-magnetic means'before and during their passage through the electroplating bath, and after such passageare automatically released by a de-energization of the electro-magnetic means. For this purpose electro-magnets are arranged in groups, one group for each sheet, on a carrying element such as a rotating drum, and the wiring circuits for the groups'of electro-magnets are so arranged that the magnets of each group will be energized so as to hold a plate magnetically at a definite position of the carrying element immediately in advance of its movement intothe 20 definite position after passing through the electroplating bath; v

The carrying element or rotating drum. may, therefore, be set in operation, the sheets to be plated may be fed thereto and the plated sheets removed therefrom while the drum is rotating continuously and without stopping or interrupting the rotation of the drum or carrying element. While the current for energizing and de-energizing may be switched on and off manually,or by any suitable'mechanical means. vthe respective currents for the drums are preferably controlled automatically.

The various features of the invention are illustrlafelcll in the accompanying drawings, in w c Fig. 1 is a. longitudinal section through a plating drum embodying a preferred form of the in- 40 tures not essential to the invention.

Fig. 2 is a cross section of the drum.

Fig. 3 is a diagrammatic sketch of the electrical connections to the several magnetic groups in the drum, and

Fig. 4 is a. part cross section of the drum similar to Fig. 2 showing the discharge of the plated sheets therefrom.

In the embodiment of the invention shown in 50 the accompanying drawings, the sheets to be plated are carried through an-electroplatingbath electroplating bath, and will be de-energized at a vention, omitting constructional details and feai6, ll and are de-energized in advance oi the pended below the surface of the drum dipping into the electroplating bath.

The metal sheets to be plated are carried through the bath Ill in succession on the cylindricalsurface of the drum ll, passing from one 5 side of the bath in Fig. 2 to the opposite side where the plated sheets are discharged. The plates are held onto the surface of the drum H by electro-magnets which are arranged in groups, the successive sheets being held by successive groups of electro-magnets.

In the embodiment shown in the accompanying drawings three groups of electro-magnets are illustrated by way of example but it will be understood that a different number. of groups may be employed.

The electro-magnets of each group are arranged in successive rows, i5, i6, I], l8, l9 and 20, the rows 15 and I6 constituting one group,

n and I8 a second group and I9 and a third 20 group. In the drawings each row, l5--20, has three electro-magnets. It will be understood that these are shown merely by way of example and I that the number of electro-magnets in a group may be increased, if desired; as may also the number of rows of electro-magnets.

Current for the electro-magnets is supplied from currentmains 2i and 22 through a hollow rotating supporting shaft l2 and suitable collector rings. Current from the main 2! flows to a collector ring 23 through a suitable brush 24 and thence flows through a wire 25 to a network of wires 28 connected to all of the electromagnets li-2ll.. The collector ring 23 is continuous and all of the electro-magnets are, therefore continuously and uninterruptedly connected to the main 3!. ,The other pole of each of the electro-magnets of each of the rows I5-20 is connected through individual conductor wires 21, 28, 29 3| and 32, respectively, to individual collector rings 33, 34, 35, 3.6, 31 and 38 which are supplied from the main. through individual brushes 3!.

The several collector rings 33-38 are not continuous but are interrupted and broken so that the respective circuits to the successive rows of electro-magnets are opened and 'closed to deenergize and energize the groups of electro-magnets in succession. In each case the first row of. each group is energized some .time in advance of the second row; for example, the electr c-magnets I5, I! and I! are energized in advance of the electro-magnets i3, i3 and 20. The latter rows de-energizing of the first rows l5, l1 and I9, as shown in Fig. 3.

In the position indicated in Fig. 3 corresponding to the position of the drum shown in Fig. 2, the contact ring 33 is just coming into contact with its respective brush 39 to energize the electro-magnets l5. Upon further rotation of the drum, through an angle of 74 in the specific embodiment shown, the collector ring 34 comes into contact with its brush 39, thereby energizing the electro-magnet l6. Meanwhile, a sheet 40 to be plated will have been inserted in the position shown in broken lines in Fig. 2, and as the drum rotates will be bent by a roller 4| to the position shown in full lines. The energizing of the electro-magnets l5 and I6 holds the two ends or edges of the sheet firmly in position on the drum. .Further rotation of the drum through an angle of 120 from its initial position brings 0 the collector ring 35 into contact with its brush 39. In this way successive rows l5, l1 and IQ of electro-magnets are energized at intervals of 120 followed in each case by the energizing of the second row l6, l8 and upon further rotation of each through an arc of 74. The ring 34 extends through an arc of about 180, whereupon it passes out of contact with the brushes 39 and de-energizes the electro-magnet IS.

The collector ring 33 extends through an are of 270 and, therefore, passes beyond its respective brush 39 and disconnects the row of electromagnets l 5 upon the further rotation of the drum I 6, as after the de-energizing of the electromagnets 16. The same relation holds true for 5 the successive electro-magnets l'I-20 and their respective collector rings. In each case, therefore, the initial row of electro-magnets is energized, then upon the rotation of the drum sufficient to bring the rear edge portion of the sheet 40 into the drum, a second row of electro-magnets is energized; then the drum rotates through 180, suflicient to carry the sheet through the electroplating bath and the rear edge of the sheet above the bath. The rear row of electro-magnets is then de-energized and the sheet straightens to the position shown in Fig. 4. Shortly thereafter the first row of electro-magnets is de-energized and the sheet falls outside of the electroplating bath, from whence it may be discharged onto a' conveying mechanism or otherwise removed. This cycle follows in endless succession for each of the groups of electro-magnets.

The drum l I is hollow and liquid proof, being formed of two end plates 42 and 43 and a cylindri-v cal plate 44 of sheet iron or other suitable metal coated throughout with an insulating and waterproofing material such as rubber. The end plates :42 and 43 project beyond the surface of the cylindrical plate 44 to form flanges 45 and 46, respectively, which serve to confine the current between the electrodes 3 and the plates or sheets 40. The end plates 42 and 43 are provided with discs 4'! of copper or brass, or other conductive material, to increase the electrical conductivity between the shaft I2 and the cylinderical wall 44. The exterior surface of the drum ll may be separated into separate electro-magnetic areas by means of partitions 48 parallel to the axis of the drum, there being two such partitions between successive groups of magnets. These longitudinally extending walls 48 enclose a space that is free from magnetic field and thus form neutral zones. The neutral zones may, however, be narrower than that indicated in the drawings, and may be dispensed with entirely. These walls 48 also have the advantage, as indicated at the right in Fig. 2, of forming a rest against which the sheet may be stopped when inserted between an electro-magnet and the roller 4|, thus enabling the sheet to be readily inserted. Also they lessen the passage of current around the edges of the sheet to the surface facing the surface of the drum I l. Openings 49 are provided in these partitions to permit the escape of air therefrom.

The sheets 40 do not rest directly on the surface of the drum but are supported on spaced contact rails 50 following the curvature of the drum and electrically connected to each other by crossbars 5| as indicated in Fig. 1.

The inner or back face of each sheet 40 is screened or shut off from the electroplating current by projecting flanges 45 and 46 and the dividing partitions 48. The sheets may be still further screened by providing a covering or sheet 52 covering the electro-magnets of each group and supported on the contact rails 50. These sheets may also be fastened directly to the heads of the electro-magnets l520. The sheet 52 would thus not only form a backing to support the sheets 40 to be plated but would also aid in distribution of current throughout the area of the sheets 40.

If the sheets 40 are relatively thin, the covering sheet 52 is preferably made of iron of high magnetic permeability or susceptibility so as to increase and distribute the magnetic flux and thus tend to hold the sheets to be plated onto the supporting sheet 52. If the sheets 40 are relatively thick, however, the supporting sheet need not be of iron because the magnetic flux is sufficiently large with thick sheets to afford good-adherence of the sheets'to the magnets and to the supporting sheet 52. To still further improve the screening effect, the rims or edges-of the supporting sheet 52 and the entire back of the sheet, except where contact is made with the rails 50,- may be coated with rubber. The rubber also serves to prevent the electro-deposition of metal at the front edge when the sheets to be plated are smaller than the supporting plate.

In order to obtain a close adherence of the sheets to be plated and the supporting sheet 52 to the end of the magnet, and to keep the curvature of the sheets relatively small, the curvature of these sheets is not continued uniformly to their ends, but is permitted to straighten somewhat as shown in Fig. 4. The magnets are correspondingly offset from a radial position.

The magnets I520 may be secured on the drums by means of a flange 53 on each magnet, which is secured in a socket on the drum by means of a screw cap 54.

The coating material which serves to insulate the drum casing may be inserted between the screw caps and the socket on the drum casing and thus serve to seal the magnets.

Through the above invention, successive sheets 40 may be inserted in position between the roller 4| and the first row, l5, l1 and I9, of a group of electro-magnets, which is thereupon energized. The rotation of the drum will cause the roller 4| to bend the sheet until its rear edge portion is brought into approximate contact with the succeeding row of electro-magnets, l6, l8 and 20, which thereupon becomes energized. The further rotation of the drum carries the plates downwardly through the electroplating bath facing the anodes I4, and then upward above the level of the electrolyte. Shortly after the rear edge of the sheet clearsthe electroplating bath, the second mitting the sheet to straighten to the position shown in Fig, 4. Thereafter :the electro-magnet I5 is de-energized and the-sheet falls outside of the electroplating bath.

It will, therefore, be apparent that the invention provides an apparatus whereby a succession of sheets may be quickly and automatically passed through an electroplating bath and with a minimum of labor. 4

What I claim is- Y 1. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath and rotatable on a horizontal axis, means to secure plates to be plated to the cylindrical surface of saiddrum, said means comprising groups of electro-magnets, there being two longitudinal rows of electro-magnets.' in each group, and means comprising collector rings and brushes to energize successively the first and last rows of each of said groups immediately before entering said bath and for de-energizing the first and last rows of each group in succession after leaving said bath. r

2. Electroplating apparatus which comprises an electroplatingbath, a drum partly immersed in said bath and rotatable on a horizontal axis, means to secure plates to be plated to the cylindrical surface of said drum, said means comprising groups of electro-magnets, there being two longitudinal rows of electro-magnets in each group, and means comprising collector rings and brushes to energize successively the first and last rows of each of said groups immediately before entering said bath and for de-energizing the first and last rows of, each group in succession after leaving said bath, said drum having means to shield the inner face of a plate held thereon.

3. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath and rotatable ona horizontalaxis, and means to secure plates to be plated to the cylindrical surface of said drum, said means comprising groups of electro-magnets, each group comprising two longitudinally disposed rows, one for the front and one for the rear edge of a plateto be plated, said drum having a hollow shaft,

collector rings on said shaft, one for each row of electro-magnets, said collector rings being interrupted at an interval and a contact brush for each said ring so positioned as to contact said ring and to close the energizing circuit for each row before entering said bath and to reach said interruption and de-energize it upon leaving said bath.

4. The apparatus of claim 3 in which the collector ring for the first row of electro-magnets of each group begins at an anglein advance of the collector ring for the second row and is interrupted at a later angle than said collector ring for the second row;

5. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath and rotatable on a horizontal axis, means to secure plates to be plated to the cylindrical surface of said drum, each of said means.

comprising two rows of electromagnets extending lengthwise of said drum at circumferentially spaced intervals, and means to energize the electro-magnets of each group immediately before they are rotated into said bath and to de-energlze said electro-magnets immediately after leaving said bath and means for pressing a plate to be plated onto the cylindrical surface of said drum between the energizing of the first row and the energizing of the second row of each group. 6. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath and rotatable on a horizontal axis,

' means to secure plates to be plated to the cylinspaced intervals, and means to energize the elec tromagnets of each group immediately before they are rotated into said bath and to de-energize said electromagnets immediately after leaving said bath and a roller extending longitudinally of said drum and approaching contact with the surface thereof ata place immediately in advance of the point ofenergizing of the first row of magnets of each group to press a plate to be plated onto the supporting surface of said drum.

'7. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath and rotatable on a horizontal axis, means to secure plates to be plated to the cylindrical surface of said drum, each of said means comprising two rows of electromagnets extending lengthwise of said drum at circumferentially spaced intervals, and means to energize the elecin said bath and rotatable on a horizontal axis,

means to secure plates to be plated to the cylindrical surface of saidvdrum, each of said means .comprising two rows of electromagnets extending lengthwise of said drum at circumferentially spaced intervals, and means to energize the electromagnets of each group immediately before they are rotated into said bath and to de-energize said electromagnets immediately after leaving said bath in which supporting rails of highly conductive metal are positioned'betweenisuccessive rows of magnets of said groups, and iron supporting plates mounted on said rails.

9. Electroplating apparatus which comprises an electroplating bath, a drum partly immersed in said bath androtatable on a horizontal axis,

means to secure plates to be plated to the cylindrical surface of said drum, each of said means comprising two rows of electromagnets extending lengthwise of said drum at circumferentially spaced intervals, and means to energize the electromagnets of each group immediately before they are rotated into said bath and to de-energize said electromagnets immediately after leaving group of electromagnets, in which said electromagnets are enclosed, means to energize the magnets of each group upon entering said bath, means to dc-energize said electromagnets of each group upon leaving said bath and 'a supporting surface for plates mounted on said drum.

MAX SCI-ILG'I'TER. 

